1. Field of the Invention
The present invention relates to a portable electronic apparatus, such as PDA, which can perform viewing and editing of the data on the screen of the display unit.
2. Description of the Related Art
The conventional compact type PDA (portable digital assistant) is aimed at the miniaturization by omitting the keyboard, and it is a portable electronic apparatus that enables the user to perform operation by the single hand. There are various products of the portable electronic apparatus which have been developed as the personal information-management tool and have been put in practical use.
For example, there is a known compact type PDA which can perform viewing and editing of the data by being interacted with the personal computer, and can perform transmission and reception of an e-mail or facsimile and accessing of the Internet by using the modem or the cellular phone.
However, since the keyboard is omitted from the compact type PDA, it is difficult to use the PDA functions only with the PDA main part, and the interaction with the personal computer is indispensable. For this reason, the compact type PDA is unsuitable for the work to input additional data newly, and the usage of the compact type PDA is limited to the viewing function of viewing the data already created on the personal computer, or the editing function of changing a part of the data already created on the personal computer.
One example of the conventional compact type PDA that is widely used is the PDA equipped with the stylus pen as the input device, instead of the mouse or the keyboard. In the PDA of this type, the stylus pen is brought into contact with the touch panel or tablet, and the absolute coordinates of the position where the point contact is made are inputted.
However, it is difficult for the user to operate the stylus pen by the single hand, and there is the problem that the user is unable to perform the viewing and editing of data easily when the user wishes to access a large amount of data on the screen.
In addition, as the conventional technology relevant to this invention, Japanese Laid-Open Patent Application No. 2002-149334 discloses a pointing device which is used for the personal computer or the like. This pointing device is small in size and has a circular shape, and it is provided with the upper-surface circular lid and the pressure sensor mechanism for the purpose of improvement in operability.
Moreover, Japanese Laid-Open Patent Application No. 09-134248 discloses a pointing input device which is used for the remote controller of the television receiving set. This pointing input device is provided with the disc-like operation button and the slide switch. The slide switch is used to detect a slide movement operation on the operation button. A pressure sensor is arranged on each of the four division regions of the operation button respectively and used to detect a depression operation on each division region of the operation button.